Assembly for an autoinjector device

ABSTRACT

An assembly for an auto injector device, the assembly including a syringe support for supporting a syringe by limiting forward axial movement of the syringe relative to the syringe support, and a guard element attachable to the syringe support by an attachment so that the guard element is axially restrained both axially forwardly and axially rearwardly relative to the syringe support by the attachment. Forwardly directed axial loads received by the guard element are transmitted to the syringe support via the attachment.

CROSS-REFERENCE APPLICATIONS

The present application is a national phase entry under 35 U.S.C. § 371of International Application No. PCT/GB2014/052387 filed Aug. 4, 2014,published in English, which claims priority from GB 1313888.8 filed Aug.2, 2013, all of which are incorporated herein by reference.

This invention relates to an assembly for an autoinjector device, and inparticular, to an assembly for an autoinjector device that reduces therisk of syringe damage during use of the autoinjector device.

BACKGROUND

Typically, pre-filled syringes supplied by pharmaceutical companies aremade from glass or similarly hard but brittle materials. Many suchpre-filled syringes are manufactured to a recognized industry “standard”and are used in autoinjector devices for delivery of the pre-filledmedicament. An example of an autoinjector device employing such astandard pre-filled syringe is described in WO-A-2007/083115 (TheMedical House plc) where, within the device, a drive element acts on theflange of the syringe to advance it axially forwardly to insert theneedle of the syringe into an injection site.

WO-A-2011/070346 (The Medical House Ltd) describes a syringe flangeprotector in the form of a spacer element that seeks to reduce the driveload applied to the syringe flange by redirecting it radially inwardlytowards the main barrel of the syringe.

There remains a need to further minimize the risk of syringe breakage inautoinjector devices, since any breakage may lead to jamming of thedevice and, ultimately, failure to deliver the dose of medicament withpotentially fatal consequences.

The present invention therefore seeks to minimize the risk of syringebreakage in autoinjector devices.

BRIEF SUMMARY OF THE DISCLOSURE

In accordance with a first aspect of the present invention there isprovided an assembly for an autoinjector device, the assembly including:

-   -   a syringe support for supporting a syringe by limiting forward        axial movement of the syringe relative to the syringe support;        and    -   a guard element attachable to the syringe support;    -   wherein the guard element is attachable to the syringe support        so that the guard element is axially restrained both axially        forwardly and axially rearwardly relative to the syringe        support, wherein attachment of the guard element to the syringe        support is by abutment of first abutment features on the syringe        support and second abutment features on the guard element;    -   wherein forward axial movement of the guard element relative to        the syringe support is limited by the abutment of the first and        second abutment features;    -   and wherein forwardly directed axial loads received by an        axially rearward surface of the guard element are transmitted to        the syringe support via the abutment of the first and second        abutment features.

Thus, the guard element is attachable to the syringe support such that,when attached, relative axial movement between the guard element and thesyringe support is limited by abutment of the first and second abutmentfeatures. That is, abutment of the first and second abutment featureslimits relative axial movement and is responsible for transferring loadapplied to the guard element to the syringe support. A syringe that maybe installed in the syringe support (prior to attachment of the guardelement) will not experience any loading that is applied to the rear ofthe guard element, since the guard element acts as a loading “bridge”that transmits load from a driving member to the syringe support withoutapplying axial loading to the syringe. In certain embodiments, the guardelement is attachable to a rear end of the syringe support.

Said second abutment features of said guard element may include aplurality of axially forwardly extending legs, and said first abutmentfeatures of said syringe support may include an external flange, andforward axial movement of the guard element relative to the syringesupport may be limited by abutment of said plurality of axiallyforwardly extending legs against said external flange. Said plurality ofaxially forwardly extending legs may form part of at least a pair ofclasps, where each clasp includes a pair of said axially forwardlyextending legs and a front cross beam extending circumferentially toconnect the two legs of each pair of axially forwardly extending legs.Each of said front cross beams may form the axially forwardmost portionof each respective clasp.

An axially forwardly facing surface of each front cross beam may betapered, the axially forwardly facing surface extending axiallyrearwardly in a radially outward direction, and an axially rearwardlyfacing surface of said external flange is also tapered in at leastparts, the axially rearwardly facing surface of said parts extendingaxially rearwardly in a radially outward direction so as to becomplementary to the axially forwardly facing surface of each frontcross beam.

The syringe support may include third abutment features and the guardelement may include fourth abutment features and rearward axial movementof the guard element relative to the syringe support is limited by theabutment of the third and fourth abutment features.

Said third abutment features of said syringe support may includeoutwardly radially extending elbows and said fourth abutment features ofsaid guard element include said front cross beams and rearward axialmovement of the guard element relative to the syringe support is limitedby the abutment of the elbows against said front cross beams. Axiallyrearwardly extending legs may extend from said elbows.

Said front cross beams may have a recessed portion for facilitatingassembly of the front cross beams over the axially rearwardly extendinglegs of said syringe support.

Said clasps may each include a second cross beam that extendscircumferentially to connect the two legs of each pair of axiallyforwardly extending legs, each second cross beam being axially rearwardand axially spaced from the respective front cross beam.

The syringe support may include hooks that are configured to latch ontothe guard element and limit rearward axial movement of the guard elementrelative to the syringe support. Each of said hooks may be disposed onan axially rearwardly extending leg of said syringe support.

The legs of each of said pair of axially forwardly extending legs ofeach clasp may be circumferentially spaced to receive one of saidaxially rearwardly extending legs of said syringe support. Said frontcross beams may have a recessed portion for facilitating assembly of thefront cross beams over the axially rearwardly extending legs of saidsyringe support.

The guard element defines an axially rearward surface for receiving anaxial drive (for causing movement of the syringe support, for example).In certain embodiments, the axially rearward surface for receiving axialdrive is an axially rearward surface of a flange.

Said guard element may define a central bore extending in an axialdirection and the flange may extend radially outwardly from the bore.The axially rearward facing surface of the flange may slope axiallyforwardly along radial directions away from said bore. Said axiallyrearward facing surface of said flange may correspond to part of thesurface of a conic frustum.

Said guard element may further comprise locating features for co-axiallyaligning the guard element with the rear end of a syringe. Said locatingfeatures may comprise an axially forwardly extending spigot extendingfrom the axially forwardly facing surface of the flange, the spigotdefining part of said bore.

The guard element may be assembled on said syringe support. The assemblymay further comprise a syringe supported by said syringe support,wherein at least part of said guard element is axially rearward of atleast part of said syringe. Said syringe may comprise a barrel having anoutlet at a forward end, a needle fluidly connected to said outlet, anopen rear end, a plunger element moveable within said barrel, a plungerrod connected to said plunger element for moving said plunger elementwithin said barrel, and a rear syringe flange extending radiallyoutwardly from a rear end of the barrel.

An axially forwardly facing side of the guard element may be shaped soas to be complementary to the profile of the rear syringe flange.

The spigot may be shaped so as to be complementary to the profile of theopen rear end of the barrel.

Axially rearward movement of the syringe received in the syringe supportmay be constrained by the guard element. In certain embodiments, somelimited axial movement of the syringe in the syringe support may bepermitted. In other embodiments, substantially no axial movement of thesyringe in the syringe support is permitted due to the presence of theguard element.

The syringe may contain a liquid drug formulation, and, in particularembodiments, the barrel of said syringe has a volume corresponding to asingle dose of said liquid drug formulation. Said liquid drugformulation may be arranged for rest at from 2-8° C. and for injecteddelivery at from 18-30° C. The liquid drug formulation may have aviscosity of less than 120 mPa·s at a delivery temperature of 20° C. Theliquid drug formulation may comprise an aqueous formulation of atherapeutic biologic type drug. Said biologic type drug may comprise animmunoglobulin or a fragment thereof. Said biologic type drug maycomprise a PEGylated or mPEGylated antibody fragment. Said aqueousformulation may comprise additional formulation component selected fromthe group consisting of buffers, NaCl, and pH modifiers. Theconcentration of the drug in the liquid drug formulation may be greaterthan 100 mg/ml.

In accordance with a second aspect of the present invention, there isprovided an autoinjector device including the assembly as describedabove.

In accordance with an example, there is provided a guard element for usewith a syringe and configured to be positioned at least partlyrearwardly of a flange of the syringe, the guard element defining acentral bore extending in an axial direction and having a flange aroundthe bore extending radially outwardly, where the flange has an axiallyforwardly facing surface and an axially rearward facing surface, and theaxially rearward facing surface slopes axially forwardly along radialdirections away from said bore and is configured for receiving axialdrive.

The guard element may further comprise locating features for locatingthe guard element on the rear end of a syringe. Said locating featuresmay comprise an axially forwardly extending spigot extending from theaxially forwardly facing surface of the flange, the spigot defining partof said bore. Said axially rearward facing surface of said flange maycorrespond to part of the surface of a conic frustum. The guard elementmay further comprise a plurality of axially forwardly extending legs.Said plurality of axially forwardly extending legs may form part of atleast a pair of clasps, where each clasp includes a pair of said axiallyforwardly extending legs and a front cross beam extendingcircumferentially to connect the two legs of each pair of axiallyforwardly extending legs. Each of said front cross beams may form theaxially forwardmost portion of each respective clasp. An axiallyforwardly facing surface of each front cross beam may be tapered, theaxially forwardly facing surface extending axially rearwardly in aradially outward direction. Said front cross beams may have a recessedportion for facilitating assembly of said guard assembly on a syringesupport. Said clasps may each include a second cross beam that extendscircumferentially to connect the two legs of each pair of axiallyforwardly extending legs and is axially rearward and axially spaced fromsaid front cross beam.

In accordance with an example, there is provided an assembly including aguard element as described above, and a syringe. Said syringe maycomprise a barrel having an outlet at a forward end, a needle fluidlyconnected to said outlet, an open rear end, a plunger element moveablewithin said barrel, a plunger rod connected to said plunger element formoving said plunger element within said barrel, and a rear syringeflange extending radially outwardly from a rear end of the barrel.

An axially forwardly facing side of the guard element may be shaped soas to be complementary to the profile of the rear syringe flange.

The spigot may be shaped so as to be complementary to the profile of theopen rear end of the barrel.

The syringe may contain a liquid drug formulation, and, in particularembodiments, the barrel of said syringe has a volume corresponding to asingle dose of said liquid drug formulation. Said liquid drugformulation may be arranged for rest at from 2-8° C. and for injecteddelivery at from 18-30° C. The liquid drug formulation may have aviscosity of less than 120 mPa·s at a delivery temperature of 20° C. Theliquid drug formulation may comprise an aqueous formulation of atherapeutic biologic type drug. Said biologic type drug may comprise animmunoglobulin or a fragment thereof. Said biologic type drug maycomprise a PEGylated or mPEGylated antibody fragment. Said aqueousformulation may comprise additional formulation component selected fromthe group consisting of buffers, NaCl, and pH modifiers. Theconcentration of the drug in the liquid drug formulation may be greaterthan 100 mg/ml.

In accordance with an example, there is provided an autoinjector deviceincluding the assembly described above.

In accordance with an example, there is provided a syringe support forsupporting a syringe by limiting forward axial movement of the syringerelative to the syringe support, the syringe support having an externalflange and hooks, each hook being disposed on an axially rearwardlyextending leg of said syringe support.

In accordance with an example, there is provided a syringe support forsupporting a syringe by limiting forward axial movement of the syringerelative to the syringe support, the syringe support having an externalflange and outwardly radially extending elbows axially rearward of theexternal flange.

The above-described syringe support may further comprise at least oneradially inward projection for supporting a syringe thereon.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are further described hereinafter withreference to the accompanying drawings, in which:

FIG. 1A is a cross-sectional view of an assembly according to anembodiment of the present invention with a syringe installed, FIGS. 1Band 1C each show a side view of the assembly of FIG. 1A where assemblyof FIG. 1C is rotated 90° relative to the assembly of FIG. 1B;

FIG. 2A shows an unassembled assembly in accordance with an alternativeembodiment of the present invention, and FIG. 2B shows a side view ofthe assembly of FIG. 2A assembled with a syringe installed;

FIG. 3A shows an unassembled assembly in accordance with a furtheralternative embodiment of the present invention, and FIG. 3B shows aside view of the assembly of FIG. 3A assembled with a syringe installed;

FIG. 4 shows a section view of an assembly according to an embodiment ofthe present invention with a syringe installed and a driving elementengaging with the assembly; and

FIG. 5 shows an autoinjector device according to an embodiment of thepresent invention.

DETAILED DESCRIPTION

FIG. 1A is a cross-sectional view of an assembly 10 according to anembodiment of the present invention. FIGS. 1B and 1C each show a sideview of the assembly of FIG. 1A where the assembly of FIG. 1C is rotated90° relative to the assembly of FIG. 1B. The assembly 10 includes asyringe support 20 and a guard element 40. In the arrangement shown inFIG. 1A, a syringe 60 is installed within the assembly 10. The syringesupport 20 supports the syringe 60 so that axial movement of the syringesupport 20 results in axial movement of the syringe 60 therein such asduring forward axial movement of the syringe support 20 and syringe 60from a pre-use position to an injection position within an autoinjectordevice. The syringe support 20 may therefore be considered to be asyringe carrier. The arrows labeled A and B in the Figures indicate the“axial” directions where A represents the forward axial direction (i.e.towards the injection site) and B represents the rearward axialdirection (i.e. away from the injection site). Other directions andorientations referred to throughout this application (for example,radial and circumferential) are relative to the axial directions A, B.The directions A and B may be considered to be parallel to a“longitudinal direction” of the assembly of the present invention, orindeed any larger device incorporating the assembly, or any componentsof the assembly.

In preferable embodiments, the syringe support 20 supports the syringe60 at a forward end of the syringe 60, for example on an internal flangeof the syringe support 20. In particularly preferable embodiments, thesyringe support 20 includes some or all of the features of the syringesupport means described in WO-A-2007/083115. However, in alternativeembodiments within the scope of the present invention, the syringe 60may be supported by the syringe support 20 at points of the syringe 60other than its forward end.

The syringe 60 may be a standard prefilled syringe and includes a barrel62 having a rear syringe flange 64 and a stopper 66 disposed within thebarrel and moveable therein. Typically, in use, the stopper 66 is movedby a plunger rod (not shown) or similar element, to pressurize fluidcontained in the barrel 62 and expel it from an open front end of thesyringe 60. The syringe 60 may include a needle (not shown) at itsforward end for penetrating an injection site and facilitating theexpulsion of fluid form the barrel 62.

The guard element 40 is a separate component relative to the syringesupport 20 and is attachable to a rear end of the syringe support 20.The attachability of the guard element 40 permits the syringe 60 to beinserted into the syringe support 20 prior to the attachment of theguard element 40. An integral guard element 40 and syringe support 60would not permit the insertion of the syringe 60 without sacrificingfeatures that give rise to the benefits associated with the presentinvention.

As shown in FIGS. 1A to 1C, the syringe support 20 is generally tubularand has an external flange 22 towards its rear end that acts as anabutment element which the guard element 40 abuts against to preventfurther forward axial movement of the guard element 40 relative to thesyringe support 20. The external flange 22 has a rearwardly facingundercut section 22 a for engaging with the guard element 40 andminimizing the risk of inadvertent movement of the guard element 40relative to the syringe support 20.

A main body 20 a of the syringe support 20 has an internal diameter thatis larger than the external diameter of the syringe barrel 62 such thatthe syringe 60 may be inserted into the syringe support 20 duringassembly. In preferable embodiments, the annular space between the mainbody 20 a of the syringe support 20 and the syringe barrel 62 (wheninstalled) is small so as to minimize radial movement of the syringe 60within the syringe support 20 thereby reducing the risk of syringe 60breakage. The internal diameter of the main body 20 a of the syringesupport 20 is smaller than the outer diameter of the rear syringe flange64 of the syringe 60 so that the rear syringe flange 64 cannot pass intothe main body 20 a. In preferable embodiments, the syringe 60 issupported in the syringe support 20 (e.g. by an abutment) such thatforward axial movement of the syringe 60 is limited relative to thesyringe support 20 to a degree where it would not be possible for therear syringe flange 64 to enter the main body 20 a in any event.Similarly, axially rearward movement of the syringe within the syringesupport is constrained by the guard element.

The external flange 22 of the syringe support 20 is located close to therear end of the main body 20 a, however it is not at the actual rear endbut axially spaced therefrom.

The syringe support 20 has a pair of rearwardly axially extending legs24 extending from the rear end of the main body 20 a axially rearward ofthe external flange 22. Each of the pair of legs 24 is diametricallyopposite the other of the pair and each extends from the main body 20 avia an elbow 24 a that extends radially outwardly. Due to the elbows 24a, the internal diameter of the legs 24 (when considered as a pair) isgreater than the internal diameter of the main body 20 a. The internaldiameter of the legs 24 is preferably similar to the outer diameter ofthe rear syringe flange 64 of the syringe 60 such that the rear flange60 may be accommodated between the legs 24 but there is minimal spacebetween the legs 24 and the rear syringe flange 64. Additionally, in thenon-limiting preferable embodiment shown in FIGS. 1A to 1C, the outerdiameter of the legs 24 (when considered as a pair) is substantially thesame as the outer diameter of the external flange 22. The legs 24 eachhave a hook 24 b that extends both radially inwardly and axiallyforwardly so as to be capable of engaging with the guard element 40 andpreventing rearward axial movement of the guard element 40 relative tothe syringe support 20 (as described in more detail below). In theembodiment shown in FIGS. 1A to 1C, the hooks 24 b are disposed at theextreme rear end of the legs 24, although in alternative embodiments,this need not necessarily be the case.

In the preferable embodiment shown in the Figures, the guard element 40has a conical or otherwise sloped rear surface 42 around a central bore44. In particular, the rear surface 42 of the guard element slopesaxially forwardly along an outwardly radial direction from the edge ofthe bore 44. The guard element 40 has an axially forwardly extendingspigot 45 that is centrally located and has an outer diameter suitablefor locating in and forming a close fit with the inside of the barrel 62of the syringe 60. An axially forwardly facing side of the guard element40 is shaped so as to be complementary to the profile of the syringeflange 64. Similarly, the spigot 45 is shaped so as to be complementaryto the profile of the barrel 62 in which it fits. Such complementaryfeatures improve the fit of the guard element 40 against the syringe 60.The spigot 45 forms a step on the axially forwardly facing side of theguard element 40 so that a surface of the guard element 40 extendsradially beyond the bore 44 and prevents the entire guard element 40from entering the inside of the barrel 62.

The guard element 40 extends radially beyond the rear syringe flange 64and has an axially forwardly extending clasp 46 that is positionedradially outward of the rear syringe flange 64 when the spigot 45 islocated in the bore 44, as shown in the Figures. The clasp 46 includes apair of circumferentially spaced legs 46 a that extend axiallyforwardly, and a cross beam 46 b that extends circumferentially betweenthe two legs 46 a, linking them together. The forwardmost surface of theclasp 46 c is beveled so as to be complementary to the rearwardly facingundercut section 22 a of the external flange 22 and be configured toengage therewith with reduced risk of inadvertent axial or radialrelative movement therebetween. This arrangement provides an abutmentthat limits forward axial movement of the guard element 40 relative tothe syringe support 20 and permits axial load to be transmitted from theguard element 40 to the syringe support 20. Whilst this is a preferableembodiment, less preferable embodiments may feature non-tapered (i.e. noaxial variation along a radial direction) interface surfaces between theclasp 46 and the external flange 22. These arrangements would stillachieve the desired abutment for limiting forward axial movement of theguard element 40 relative to the syringe support 20 but would be lesseffective at minimizing the risk of the clasp 46 inadvertently flexingradially outwardly and sliding axially forwardly over the externalflange 22.

In the preferable embodiment shown in the Figures, the circumferentialspace between the two legs 46 a of the clasp 46 accommodates therearwardly axially extending legs 24 of the syringe support 20.Additionally, the guard element 40 has a pair of axially rearwardlyfacing receiving surfaces 48 for receiving the hooks 24 b of the legs ofthe syringe support 20 where each of the axially rearwardly facingreceiving surfaces tapers axially rearwardly in a radially outwardlydirection so as to be complementary to the forward facing surface ofeach hook 24 b. When engaged on the axially rearwardly facing receivingsurfaces 48, the hooks 24 b limit rearward axial movement of the guardelement 40 relative to the syringe support 20. The combination of theabutment between the clasp 46 and the external flange 22 and theengagement of the hooks 24 b on the axially rearwardly facing receivingsurfaces 48 results in the guard element 40 being limited in both theforward and rearward axial directions relative to the syringe support 20and therefore being axially “captured” relative thereto. Some smallrelative axial movement may be possible due to manufacturing tolerances,however it is preferable for any axial movement to be as small aspossible.

The guard element 40 forms a loading bridge that transmits axial forcereceived from the rear of the guard element axially forwardly into thesyringe support 20 via the external flange 22. The assembly isconfigured so that no axial load is transmitted from the guard element40 to the syringe 60, and the syringe is therefore protected frompotentially damaging forces during use. One factor that contributes tothe syringe avoiding applied axial loading is the relationship betweenthe supporting of the syringe by the syringe support 20 and therespective axial lengths of the clasps 46 and the axially rearwardlyextending legs 24 of the syringe support 20. To avoid loading, thesyringe 60 should be “floating” within the assembly 10 of the syringesupport 20 and the guard element 40. That is, some limited axialmovement of syringe in the syringe support may be permitted.

FIGS. 2A and 2B show a modified assembly 10′ in accordance with analternative embodiment of the present invention. The modified assembly10′ includes a modified guard element 40′ and a modified syringe support20′. The modified guard element 40′ and syringe support 20′ are eachlargely the same as the guard element 40 and syringe support 20described above in relation to FIGS. 1A to 1C, however modifiedcomponents are indicated with a prime/dash (′) and newcomponents/features are indicated by a new numeral. For example, themodified guard element 40′ of FIGS. 2A and 2B has a modified clasp 46′that differs in two respects in comparison with the clasp 46 of FIGS. 1Ato 1C. The modified clasp 46′ still includes two pairs ofcircumferentially spaced legs 46 a′ that extend axially forwardly, and across beam 46 b′ that extends circumferentially between the two legs 46a′ of each pair, linking the respective pair together. However, eachcross beam 46 b′ includes a recessed portion 47 on its radially inwardside. Each recessed portion 47 is tapered so as to facilitate assemblyof guard element 40′ onto the syringe support 20′ by assisting theclasps 46′ over the modified axially rearwardly extending legs 24′ ofthe modified syringe support 20′.

Secondly, the legs 46 a′ of the clasp 46′ are wider in a circumferentialdirection in comparison with the legs 46 a of the guard element 40 ofFIGS. 1A to 1C. This widening is possible since the axially rearwardlyextending legs 24′ of the modified syringe support 20′ are narrower in acircumferential direction in comparison with the legs 24 of FIGS. 1A to1C. The wider legs 46 a′ of the clasp 46′ improve cross-sectional areastrength and reduce the risk of the guard element 40′ breaking ordeforming under load.

Additionally, the axially rearwardly extending legs 24′ are tapered inan axial direction, with the legs 24′ increasingly widening in acircumferential direction along the axial rearward direction. Theaxially rearwardly extending legs 24′ form a close fit with the clasp46′ and reduce “rocking” of the guard element 40′ relative to thesyringe support 20′ along directions indicated by double arrow C in FIG.2B. Rocking may alternatively be mitigated where the clasp 46′ does notnecessarily form a close fit entirely around the legs 24′ by lugslocated on either of the legs 24′ or the clasp 46′ for at least forminga close fit at selected locations and minimized relative movement.

FIGS. 3A and 3B show an alternative embodiment of an assembly 10″ inaccordance with the present invention. The modified assembly 10″includes a modified guard element 40″ and a modified syringe support20″. The modified guard element 40″ and syringe support 20″ are eachlargely the same as the guard element 40 and syringe support 20described above in relation to FIGS. 1A to 1C, however modifiedcomponents are indicated with a double prime/dash (″) and newcomponents/features are indicated by a new numeral. The modified clasp46″ still includes two pairs of circumferentially spaced legs 46 a″ thatextend axially forwardly, and a cross beam 46 b″ that extendscircumferentially between the two legs 46 a″ of each pair, linking therespective pair together. Additionally, the clasp 46″ has a rear crossbeam 46 d axially rearward and axially spaced from the cross beam 46 b″,where the rear cross beam 46 d extends circumferentially between thelegs 46 a″. The pair of cross-beams 46 d, 46 b″ and the pair of legs 46a″ define an aperture for receiving the axially rearwardly extendinglegs 24″.

As shown in FIGS. 3A and 3B, the axially rearwardly extending legs 24″of the modified syringe support 20″ are axially shorter than the legs24,24′ of FIGS. 1A-1C and FIGS. 2A-2B. The legs 24″ do not have radiallyinwardly extending hooks (c.f. hooks 24 b,24 b′) and do not latch ontorearwardly facing receiving surfaces (c.f. rearwardly facing receivingsurfaces 48). Instead, the elbow 24 a″ of the legs 24″ abut against thecross beam 46 b″ to limit rearward axial movement of the guard element40″ relative to the syringe support 20″. In the assembled configuration,as shown in FIG. 3B, there is an axial gap between the axially forwardlyfacing side of the elbow 24 a″ and the axially rearwardly facing side ofthe cross beam 46 b″. This gap determines the degree of possiblerelative axial movement between the guard element 40″ and the syringesupport 20″. In preferable embodiments, the elbow 24 a″ may be tapered,extending axially forwardly in a radially outward direction, to engagewith a complementary rearwardly facing surface of the cross beam 46 b″.In this preferable arrangement, the clasp 46″ engages more firmly withthe syringe support 20″ when moved axially rearwardly relative thereto,as the risk of the clasp 46″ deforming so as to slide over the legs 24″is reduced.

The rearwardly axially extending legs 24,24′ of the embodimentsdescribed above in relation to FIGS. 1A to 1C and 2A to 2B may alsoinclude an elbow, where the cross beam 46 b,46 b′ abuts the elbow tolimit rearward axial movement of the guard element 40,40′ in theunlikely event that the hooks 24 b,24 b′ fail.

The guard element 40″ of FIGS. 3A and 3B is shown with the recessedportion 47 present on each clasp 46″. Whilst it is preferable for thisfeature to be present and assist assembly of the guard element 40″ ontothe syringe support 20″, embodiments within the scope of the presentinvention may not have this feature, but retain the other describedfeatures of the embodiment of FIGS. 3A and 3B. Indeed, the recessedportion 47 may or may not be present on the clasps 46,46′,46″ within thescope of the present invention.

Similarly, whilst the rear surface 42 of the guard elements 40,40′,40″is described above as being conical or otherwise sloped, in alternativeembodiments within the scope of the present invention, the rear surface42 may not be sloped (i.e. not varying axially along a radialdirection). Such embodiments may still include any of the describedfeatures of the embodiments of FIGS. 1A-1C, 2A-2B and 3A-3C. It isnoted, however, that a conical or otherwise sloped rear surface 42 ispreferable in that it facilitates a driving member to cease contact withthe guard element 40,40′,40″ once the driving member has acted thereonto move the syringe support 20,20′,20″ (and hence syringe 60 containedtherein) to a position suitable for delivery (i.e. when a needle of thesyringe 60 has penetrated an injection site to a sufficient depth). Forexample, a conical or otherwise sloped rear surface 42 is particularlysuitable for use in autoinjectors having driving elements that haveflexible legs or tags that initially engage with the guard element40,40′,40″ to apply a load to the syringe support 20,20′,20″ to move thesyringe 60, and then flex radially outwardly into an aperture of ahousing of the autoinjector when a specific axial position is reached.The conical or otherwise sloped surface 42 will reduce the risk of theflexible legs or tags failing to flex into the aperture and thusdisengaging with the guard element 40,40′,40″ which may cause the deviceto jam and the dose of medicament to not be delivered. Guard elements40,40′,40″ having a conical or otherwise sloped rear surface 42 areparticularly suited for use in devices where the drive element isequivalent to the inner housing component described in the publicationWO-A-2005/070481.

FIG. 4 shows an example of an assembly 10 with a syringe 60 installed.Also shown is a drive element 80 having flexible legs 82 towards aforward end thereof. Each flexible leg 82 has a foot 82 a at a forwardend for engaging with the guard element 40. In the configuration shownin FIG. 4, the flexible legs 82 are flexed radially inwardly and areengaged with the guard element 40 so as to be capable of transmittingaxial force thereto. Typically, the flexible legs 82 will be biased intotheir radially inward position due to interference with an outer sleeveor housing whose surface prevents radial outward flexing. Apertures orother suitable recesses or formations at predetermined axial locationson the outer sleeve or housing permit the flexible legs 82 to flexradially outwardly at a particular axial position. The conical orotherwise sloped surface 42 allow an adequate engagement between thedrive element 80 and the guard element 40, but facilitate easy andreliable disengagement when the flexible legs 82 reach the predeterminedaxial location. The relationship and engagement/disengagement shown inand described in relation to FIG. 4 is not exclusive to the guardelement described above using reference numeral 40. Indeed, thedescribed relationship and engagement/disengagement may apply to any ofguard elements 40′,40″ or any other guard element within the scope ofthe present invention.

Whilst it is preferable for the guard element of the present inventionto act as a loading bridge that transmits axial force received from therear of the guard element axially forwardly into the syringe support 20,the conical or otherwise sloped surface provides advantages that areindependent of the preferable bridging feature. Therefore, according tosome embodiments of the present invention, the guard element may have aconical or otherwise suitably sloped rearward facing surface but nothave features that permit the guard element to behave as a loadingbridge. Without the loading bridge features, axial forces received fromaxially rearward of the guard element will be transmitted directlythrough the guard element to the syringe on which the guard element isdisposed and located. Thus, these embodiments will not mitigate thepotential impact damage noted above to the same extent as theembodiments with the bridging features, however, it will provide asuitable rear surface for receiving the flexible legs of a drivingelement and facilitating easy and reliable disengagement. The risk ofjamming is therefore reduced when used in an autoinjector device.

The assembly of the invention may form part of an autoinjector device.FIG. 5 shows an example of an autoinjector device 100 that mayincorporate the assembly. The autoinjector device 100 shown in FIG. 5includes a main body 102, a cap 104 removably attached to a front end ofthe main body 102, and a button 106 for actuating the autoinjectordevice 100.

The assembly and autoinjector of the invention is suitable for theinjected delivery of drug, particularly for the treatment and/orprophylaxis of a number of diseases, disorders or conditions, includinginfections (viral, e.g. HIV infection, bacterial, fungal and parasitic);endotoxic shock associated with infection; inflammatorydiseases/autoimmunity such as osteoarthritis, rheumatoid arthritis,psoriatic arthritis, systemic lupus erythematosus (SLE), ankylosingspondilitis, COPD, asthma, Alzheimer's Disease, Crohn's disease,ulcerative colitis, irritable bowel syndrome and psoriasis; immunemediated inflammatory disorders of the central and peripheral nervoussystem such as multiple sclerosis and Guillain-Barr syndrome;graft-versus-host disease; organ transplant rejection; pain; cancer(including solid tumours such as melanomas, hepatoblastomas, sarcomas,squamous cell carcinomas, transitional cell cancers, ovarian cancers andhematologic malignancies, acute myelogenous leukaemia, chronicmyelogenous leukemia, gastric cancer and colon cancer); congenitaldisorders, e.g. cystic fibrosis and sickle cell anaemia; growthdisorders; epilepsy; treatment of infertility; heart disease includingischaemic diseases such as myocardial infarction as well asatherosclerosis and intravascular coagulation; bone disorders such asosteopenia and osteoporosis; and metabolic/idiopathic disease, e.g.diabetes.

In embodiments, the syringe of the assembly and autoinjector hereincontains a liquid drug formulation, which is designed for refrigeratedrest (e.g. at from 2-8° C.) and for injected delivery at roomtemperature (e.g. at or about 18-30° C.). In embodiments, the viscosityof the liquid drug formulation is less than 120 mPa·s (120 centipoise),in embodiments less than 100 mPa·s (100 centipoise) at a deliverytemperature of 20° C.

Appropriate drugs may thus be selected from biologically active agents,including chemical entities, polysaccharides, steroids and, especially,naturally occurring and recombinant proteins, including glycoproteins,polypeptides and oligopeptides and polymeric derivatives thereof.Particular proteins, polypeptides and oligopeptides include hormones,such as insulin, epinephrine, norepinephrine, adrenocorticotrophin,somatotropin, erythropoietin and oxytocin; cytokines, such aslymphokines, chemokines and interleukins and receptors therefor, e.g.interleukin (IL)-1α, IL-1β, IL-1R, IL-2, IL-3, IL-4, IL-5, IL-6, IL-13,IL17, interferon (IFN)-α, IFN-β, IFN-γ, granulocyte monocyte colonystimulating factor, tumour necrosis factor-a; growth factors, such asnerve growth factor and platelet-derived growth factor; enzymes, such astissue plasminogen activator; and, especially, immunoglobulins.Immunoglobulins include whole antibodies and functionally activefragments and/or derivatives thereof, for example polyclonal,monoclonal, recombinant, multi-valent, mono- or multi-specific,humanised or chimeric antibodies, single chain antibodies, Fabfragments, Fab′ and F(ab′)2 fragments. Polymeric derivatives of suchproteins, polypeptides and oligopeptides include derivatives formedbetween the protein, polypeptide or oligopeptide and a naturallyoccurring or synthetic polymer, e.g. a polysaccharide or a polyalylklenepolymer such as a poly(ethyleneglycol) [PEG] or derivative thereof, e.g.methoxypoly(ethyleneglycol) [mPEG]. Particular agents include growthhormones and hormones for the treatment of infertility. Other particularagents are for the treatment of epilepsy such as brivaracetam andseletracetam.

The autoinjector device herein has been found to be of particularutility where the drug is an immunoglobulin or a fragment thereof,especially a PEGylated or mPEGylated antibody fragment.

The liquid drug formulations herein are typically aqueous formulations,which comprise the drug in solution and additionally other optionalformulation components, which may include buffers (e.g. lactate,acetate), NaCl, and pH modifiers (e.g. NaOH).

The assembly and autoinjector device herein has been found to be ofparticular utility wherein the concentration of the drug (e.g. atherapeutic biologic type drug) in the liquid drug formulation is quitehigh. In particular, where the drug is a pegylated antibody theauto-injector device has been found to be of particular utility whereinthe concentration of the drug is greater than 100 mg/ml, particularlygreater than 150 mg/ml such as 200 mg/ml.

Throughout the description and claims of this specification, the words“comprise” and “contain” and variations of them mean “including but notlimited to”, and they are not intended to (and do not) exclude othermoieties, additives, components, integers or steps. Throughout thedescription and claims of this specification, the singular encompassesthe plural unless the context otherwise requires. In particular, wherethe indefinite article is used, the specification is to be understood ascontemplating plurality as well as singularity, unless the contextrequires otherwise.

Features, integers, characteristics, compounds, chemical moieties orgroups described in conjunction with a particular aspect, embodiment orexample of the invention are to be understood to be applicable to anyother aspect, embodiment or example described herein unless incompatibletherewith. All of the features disclosed in this specification(including any accompanying claims, abstract and drawings), and/or allof the steps of any method or process so disclosed, may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. The invention is notrestricted to the details of any foregoing embodiments. The inventionextends to any novel one, or any novel combination, of the featuresdisclosed in this specification (including any accompanying claims,abstract and drawings), or to any novel one, or any novel combination,of the steps of any method or process so disclosed.

The reader's attention is directed to all papers and documents which arefiled concurrently with or previous to this specification in connectionwith this application and which are open to public inspection with thisspecification, and the contents of all such papers and documents areincorporated herein by reference.

The invention claimed is:
 1. An assembly for an autoinjector device, theassembly including: a syringe support for carrying a syringe installedtherein, wherein the syringe support supports the syringe at a forwardend of the syringe such as to limit forward axial movement of thesyringe relative to the syringe support; and a guard element attachableto the syringe support; wherein the guard element is attachable to thesyringe support so that the guard element is axially restrained bothaxially forwardly and axially rearwardly relative to the syringesupport, wherein attachment of the guard element to the syringe supportincludes abutment of first abutment features on the syringe support andsecond abutment features on the guard element; wherein abutment of thefirst and second abutment features prevents forward axial movement ofthe guard element relative to the syringe support; and wherein forwardlydirected axial loads received by an axially rearward surface of theguard element are transmitted to the syringe support via the abutment ofthe first and second abutment features without applying axial loading toa syringe carried by the syringe support.
 2. An assembly according toclaim 1, wherein the guard element is attachable to a rear end of thesyringe support.
 3. An assembly according to claim 1, wherein the secondabutment features of the guard element include a plurality of axiallyforwardly extending legs, and the first abutment features of saidsyringe support include an external flange, and forward axial movementof the guard element relative to the syringe support is limited byabutment of said plurality of axially forwardly extending legs againstsaid external flange.
 4. An assembly according to claim 3, wherein saidplurality of axially forwardly extending legs form part of at least apair of clasps, where each clasp includes a pair of the axiallyforwardly extending legs and a front cross beam extendingcircumferentially to connect the two legs of each pair of axiallyforwardly extending legs.
 5. An assembly according to claim 4, whereineach of said front cross beams forms the axially forwardmost portion ofeach respective clasp.
 6. An assembly according to claim 5, wherein anaxially forwardly facing surface of each front cross beam is tapered,the axially forwardly facing surface extending axially rearwardly in aradially outward direction, and an axially rearwardly facing surface ofsaid external flange is also tapered in at least parts of said externalflange, the axially rearwardly facing surface of said external flange atsaid parts of said external flange extending axially rearwardly in aradially outward direction so as to be complementary to the axiallyforwardly facing surface of each front cross beam.
 7. An assemblyaccording to claim 4, wherein the syringe support includes thirdabutment features and the guard element includes fourth abutmentfeatures and rearward axial movement of the guard element relative tothe syringe support is limited by the abutment of the third and fourthabutment features.
 8. An assembly according to claim 7, wherein thethird abutment features of the syringe support include outwardlyradially extending elbows and the fourth abutment features of said guardelement include said front cross beams and rearward axial movement ofthe guard element relative to the syringe support is limited by theabutment of the elbows against said front cross beams.
 9. An assemblyaccording to claim 8, wherein axially rearwardly extending legs extendfrom said elbows.
 10. An assembly according to claim 9, wherein saidfront cross beams have a recessed portion for facilitating assembly ofthe front cross beams over the axially rearwardly extending legs of saidsyringe support.
 11. An assembly according to claim 8, wherein saidclasps each include a second cross beam that extends circumferentiallyto connect the two legs of each pair of axially forwardly extendinglegs, each second cross beam being axially rearward and axially spacedfrom the respective front cross beam.
 12. An assembly according to claim4, wherein the syringe support includes hooks that are configured tolatch onto the guard element and limit rearward axial movement of theguard element relative to the syringe support.
 13. An assembly accordingto claim 12, wherein each of said hooks is disposed on an axiallyrearwardly extending leg of the syringe support.
 14. An assemblyaccording to claim 1, wherein the axially rearward surface is an axiallyrearward surface of a flange.
 15. An assembly according to claim 14,wherein said guard element defines a central bore extending in an axialdirection and the flange extends radially outwardly from the bore. 16.An assembly according to claim 15, wherein the axially rearward facingsurface of the flange slopes axially forwardly along radial directionsaway from said bore.
 17. An assembly according to claim 15, wherein saidguard element further comprises locating features for co-axiallyaligning the guard element with the rear end of a syringe.
 18. Anassembly according to claim 17, wherein said locating features comprisean axially forwardly extending spigot extending from an axiallyforwardly facing surface of the flange, the spigot defining part of saidbore.
 19. An assembly according to claim 18, wherein the guard elementis assembled on the syringe support.
 20. An assembly according to claim19, further comprising a syringe supported by said syringe support,wherein at least part of said guard element is axially rearward of atleast part of said syringe.
 21. An assembly according to claim 20,wherein said syringe comprises a barrel having an outlet at a forwardend, a needle fluidly connected to said outlet, an open rear end, aplunger element moveable within said barrel, a plunger rod connected tosaid plunger element for moving said plunger element within said barrel,and a rear syringe flange extending radially outwardly from a rear endof the barrel.
 22. An assembly according to claim 21, wherein an axiallyforwardly facing side of the guard element is shaped so as to becomplementary to the profile of the rear syringe flange.
 23. An assemblyaccording to claim 21, wherein the spigot is shaped so as to becomplementary to the profile of the open rear end of the barrel.
 24. Anassembly according to any of claim 20, wherein the syringe contains aliquid drug formulation.
 25. An assembly according to claim 24, whereinthe barrel of said syringe has a volume corresponding to a single doseof said liquid drug formulation.
 26. An assembly according to claim 24,wherein the liquid drug formulation comprises an aqueous formulation ofa therapeutic biologic type drug.
 27. An assembly according to claim 14,wherein said axially rearward facing surface of said flange correspondsto part of the surface of a conic frustum.
 28. An assembly according toclaim 1, wherein abutment of the first and second abutment features actsas an end-stop to prevent forward axial movement of the guard elementrelative to the syringe support.
 29. An assembly according to claim 1,wherein the syringe support has a generally tubular body arranged forinsertion therein of a syringe barrel of the syringe.
 30. An assemblyfor an autoinjector device, the assembly including: a syringe supportfor supporting a syringe by limiting forward axial movement of thesyringe relative to the syringe support; and a guard element attachableto the syringe support; wherein the guard element is attachable to thesyringe support so that the guard element is axially restrained bothaxially forwardly and axially rearwardly relative to the syringesupport, wherein attachment of the guard element to the syringe supportincludes abutment of first abutment features on the syringe support andsecond abutment features on the guard element; wherein forward axialmovement of the guard element relative to the syringe support is limitedby the abutment of the first and second abutment features; whereinforwardly directed axial loads received by an axially rearward surfaceof the guard element are transmitted to the syringe support via theabutment of the first and second abutment features; wherein the secondabutment features of the guard element include a plurality of axiallyforwardly extending legs, and the first abutment features of saidsyringe support include an external flange, and forward axial movementof the guard element relative to the syringe support is limited byabutment of said plurality of axially forwardly extending legs againstsaid external flange; wherein said plurality of axially forwardlyextending legs form part of at least a pair of clasps, where each claspincludes a pair of the axially forwardly extending legs and a frontcross beam extending circumferentially to connect the two legs of eachpair of axially forwardly extending legs; wherein the syringe supportincludes hooks that are configured to latch onto the guard element andlimit rearward axial movement of the guard element relative to thesyringe support; wherein each of said hooks is disposed on an axiallyrearwardly extending leg of the syringe support; and wherein the legs ofeach of said pair of axially forwardly extending legs of each clasp arecircumferentially spaced to receive one of said axially rearwardlyextending legs of said syringe support.
 31. An assembly according toclaim 30, wherein said front cross beams have a recessed portion forfacilitating assembly of the front cross beams over the axiallyrearwardly extending legs of said syringe support.
 32. An autoinjectordevice including the assembly of claim
 19. 33. An assembly for anautoinjector device, the assembly including: a syringe support forcarrying a syringe installed therein, by limiting forward axial movementof the syringe relative to the syringe support; and a guard elementattachable to the syringe support; wherein the guard element isattachable to the syringe support so that the guard element is axiallyrestrained both axially forwardly and axially rearwardly relative to thesyringe support, wherein attachment of the guard element to the syringesupport includes abutment of first abutment features on the syringesupport and second abutment features on the guard element; whereinabutment of the first and second abutment features prevents forwardaxial movement of the guard element relative to the syringe support;wherein forwardly directed axial loads received by an axially rearwardsurface of the guard element are transmitted to the syringe support viathe abutment of the first and second abutment features without applyingaxial loading to a syringe carried by the syringe support; wherein theaxially rearward surface is an axially rearward surface of a flange;wherein said guard element defines a central bore extending in an axialdirection and the flange extends radially outwardly from the bore;wherein said guard element further comprises locating features forco-axially aligning the guard element with the rear end of a syringe;and wherein said locating features comprise an axially forwardlyextending spigot extending from an axially forwardly facing surface ofthe flange, the spigot defining part of said bore.